Question

What is the number of zeros at end of number 28! + 29!?


ans-7; What is the number of zeros at end of number 28! + 29!?; ans-7

Answer 1

there will be 7 zeros at the end in the above question

Answer 2

Answer:

Number of zeros at the end of the number 28!+29! are 7

Step-by-step explanation:

The given number is

$28! + 29!$

It can be reframed as given below-

$28! + 29! = 28! + 29 \times 28! \\ = 28! (29 + 1) \\ = 30 \times 28!$

This can be written as

$30(28 \times 27 \times 26 \times 25 \times 24 \times .. \times 20 \times ..15 \times .. \times 12 \times ...10 \times ...5 \times ..2 \times 1)$

In above expansion we get zero during the multiplication of the terms as mentioned below

$30(24 \times 25 \times 20 \times 15 \times 12 \times 10 \times 5 \times 2 \times ....) = 30 \times 216000000 \times (23 \times 22 \times 21...) \\ = (23 \times 22 \times ...) \times 6480000000$

Hence number of zeros at the end of number are 7.

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